1. Field of the Invention
The present invention relates to a structure of a pluggable optical transceiver, and a method for manufacturing the same.
2. Related Prior Art
The pluggable transceiver 1 (hereinafter denoted as transceiver) shown in FIG. 1A is used by being inserted into the cage 2 provided on the circuit board of the host system. The transceiver 1 inserted into the cage 2 is shown in FIG. 1B. On the bottom of the cage 2 are formed stud pins 2c, and the cage 2 is installed on the circuit board of the host system by soldering these stud pins 2c to the circuit board so as to expose the opened end 2a from the face panel of the host system. In the inner end of the cage 2 is provided an electrical connector 2b such that each electrode of the connector 2b is in contact to, or soldered to the wiring pattern on the circuit board. By inserting the transceiver 1 into this cage 2, the electrical plug configured in the rear end of the transceiver 1, mates with this connector 2b within the cage to enable the transceiver 1 to communicate with the host system. In FIG. 1B, the host system, the circuit board and the face panel thereof, are omitted. Moreover, to configure the electrode of the plug makes the transceiver 1 so-called host-pluggable, by which the transceiver 1 is able to insert into/remove from the cage 2 as the host system is powered on.
The cage 2, as shown in FIG. 1B, is a metal box with one end 2a being opened. Although a tip of the tab plate protrudes from the cover 23 of the transceiver 1, when the transceiver 1 is set within the cage 2, this tab plate 14 is also set within the cage 2 as the tip thereof coming in contact to the inside of the cage 2. Moreover, a plurality of fins 2d extends outward in the front portion thereof to surround the opened end 2a. When the cage 2 is installed on the circuit board of the host system, these fins 2a come in electrically contact to the face panel to shield the transceiver 1 and the host system.
Some multi-source agreements (MSA) rule the outer dimension and the electrical specification for such pluggable transceiver. The normal operation can be ensured as long as the transceiver follows the agreements, even when such transceiver is provided from the extraordinary manufacturer. Further, since the agreement rules the outer dimension, the insertion/extraction of the transceiver is also ensured.
However, the cage itself is made of a thin metal plate to deform in ease by an extra force, even by the insertion/extraction of the transceiver to the cage. The tab plate is necessary to come in reliable in contact to such deformed cage. The tab plate is provided to secure the EMI (Electro-Magnetic Interference) shield function for the transceiver 1. Recently, the operational speed, i.e., the clock speed of the transceiver reaches and exceeds 1 GHz. In such high speed operation, the high frequency signal is firmly prevented from leaking from the equipment. The tab plate is necessary to come in contact to the physically deformed cage 2.
Another subject under such high operational speed is that, the active devices, such as ICs and transistors, installed within the transceiver becomes necessary to be provided with large current to operate in a high frequency band, which results in the further heat being generated in the devices and the request to provide a further effective mechanism for the heat dissipation. However, the transceiver is unable to touch the case thereof in tight to the cage because the pluggable transceiver is inherently assumed to be inserted into/extracted from the cage 2. Tightly and firmly touching to the cage disturbs the smooth insertion/extraction of the transceiver.
Further, the transceiver comprises of three parts, namely, subassemblies to covert an optical signal to an electrical signal, or an electrical signal to an optical signal, a body portion installing the electronic circuit and an optical receptacle, and a mechanism to engage the transceiver with the cage. The U.S. Pat. No. 6,349,918 has disclosed the engaging mechanism using a bail and an actuator. Rotating the bail in front of the optical receptacle, one end of the bail pushes up the actuator, accordingly, the other end of the actuator is pressed down to disengage with the cage because the actuator moves in the seesaw motion. The other U.S. patent published as 2003/0142917A has also disclosed a similar mechanism.
Recently, one application has been proposed that, a plurality of transceivers is arranged in dense to configure a hub system for the optical communication. For example, to arrange the transceiver, the cross section of which is about 1 centimeter square, by 16 pieces in horizontal and two to four in vertical forms the hub system providing 32 to 64 optical channels. In such system, when the target transceiver is to be removed from the cage as the other cages surrounding the target transceiver are set with transceivers each providing an optical cable, the bail of the target transceiver is hard to rotate because the neighbor transceivers and their optical cables prevent from touching thereto, which prohibit the target transceiver from being extracted from the cage.
Therefore, the present invention is to provide a new structure of the optical pluggable transceiver based on the MSA and a method for manufacturing the same. The transceiver according to the present invention, not only satisfies the MSA standard, but also ensures the reliable shielding by stably touching to the cage, provides the effective heat dissipation mechanism from the devices to the outside thereof, and provides a disengaging mechanism with the cage even a plurality of transceivers with the optical cable is densely arranged.